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Fleetwood Mac photographed circa 1977.
As the opening track on 1975's five-times-platinum Fleetwood Mac album, "Monday Morning" was the first thing most fans heard from the new incarnation of the band after Lindsey Buckingham and Stevie Nicks joined. But the song also revealed a new Buckingham. You can listen to an exclusive early take of the song, from the upcoming Fleetwood Mac deluxe edition, below.

The singer-guitarist and his then-girlfriend Nicks joined Fleetwood Mac at the recommendation of co-producer Keith Olsen, after releasing their own Buckingham Nicks album. And Buckingham freely acknowledges that becoming part of a group required him to adjust his approach to music.

"If you go all the way back to before Stevie and I joined Fleetwood Mac, the application of guitar was a lot more prevalent in the whole scheme of the space that was taken and the work that was done by a particular instrument," Buckingham, who wrote the buoyant, surging "Monday Morning" for a second Buckingham Nicks album, told Billboard previously. "I wasn't even sure what my role was gonna be at that point; Obviously it was kind of a lesson in adaptation for me, and maybe giving up on certain things and concentrating on other things which were maybe strengths for the good of the band. So part of the exercise of joining Fleetwood Mac was adapting down to not only fit a sound, but I had to get off the guitar I was using and get on to a Les Paul. Their sound was very fat, and the nature of the playing with Christine (McVie) and John (McVie), there was a lot of space taken, so you had to sort of take what was left and fit into it."

He clearly figured it out. Fleetwood Mac (aka The White Album) was the veteran group's most successful to that point, hitting No. 1 on the Billboard 200 during the summer of 1976 and spawning three Hot 100 top 20 hits in "Over My Head," "Rhiannon" and "Say You Love Me." It also established a new creative partnership between Buckingham and Christine McVie -- directly via their co-write of the track "World Turning" but also with Buckingham as a sounding board for McVie's other songs, a relationship that came to full fruition with last year's Lindsey Buckingham Christine McVie duo album.

"It just came from this chemistry that I can't really analyze," explained Buckingham. "I remember being in rehearsals with Christine and the rest of the band before we cut that first album and we were running down song ideas. But it was so clear that right away that Christine and I had this thing. She was just really looking for direction. She was open to me taking liberties with her songs. So early on, that was probably the first thing that hit me about being in Fleetwood Mac was being extremely aware that I had something to contribute to Christine's songs as a producer and possibly as a co-writer.

"I think we just have this mutual respect as musicians and as artists. We're both really grounded in our craft, and I think in the same way she's filled in the middle ground between one pole and another pole that Stevie and I might represent, you know, on the right and the left, I think that when you make it just the two of us it's that thing. It sort of naturally unites."

The Fleetwood Mac: Deluxe Edition comes out Jan. 19 in a variety of formats, the expanded editions including more unreleased early takes and live tracks. The band, meanwhile, is expected to be touring during the coming year, though Buckingham also has a solo album that's due out this year. "I think the earliest anyone expected to be back on the road with Fleetwood Mac might've been spring of 2018," Buckingham said last year. "Stevie, my understanding is that she's all ready. I've got this solo album; I'm the one who's holding it up. But, you know, that's typical for us. There's a lot of moving parts so, you know, you gotta wait for everyone to be ready."

"It just came from this chemistry that I can't really analyze," explained Buckingham. "I remember being in rehearsals with Christine and the rest of the band before we cut that first album and we were running down song ideas. But it was so clear that right away that Christine and I had this thing. She was just really looking for direction. She was open to me taking liberties with her songs. So early on, that was probably the first thing that hit me about being in Fleetwood Mac was being extremely aware that I had something to contribute to Christine's songs as a producer and possibly as a co-writer.